Since its inception, TommyxGigi has been a hit with shoppers—and Tommy Hilfiger is one of the few brands that not only was an early supporter of the shift toward a consumer-facing fashion show (i.e., one where all the items shown on the runway would be available for purchase right after), but also stuck with it…and successfully, at that.

Backstage at the spring 2018 show, Hilfiger told Glamour that he likes to call the TommyxGigi “a ‘youthquake,’ because when Gigi joined us, she was like a magnet, bringing young people to [us]. By signing on Hadid as a codesigner, the designer explained, the collections attracted a new audience—specifically, millennials—that might have heard of the label, but wasn’t necessarily shopping it. “I never want to be a brand that ages out,” he added.

So much of the recent Tommy Hilfiger collections, especially since Hadid signed on four seasons ago, have been self-referential: big logos, sportswear, and retro silhouettes…all pieces that feel as if they could’ve been thrifted, old-school Tommy Jeans. That came from the 22-year-old, who specifically set out to resurrect items from the Tommy Hilfiger archive in order to “make my generation and my fans excited about it again,” she said. “We get to have a taste of the stuff we missed. That’s why it’s so exciting—I wanted to bring my own celebration of Tommy back.”

Whether or not the 2018 customer gets the callback when they see the clothes on a hanger, the strategy seems to be paying off: In a post-#TommyxGigi landscape, “we have parents coming in and saying, ‘My daughter sent me in to buy a Gigi top or a Gigi jacket,’” said Hilfiger.

Plus, the “immediate gratification” of a “see now, buy now” model has resonated with the customer, according to the designer: “They see it—especially when they see it on Gigi—they want to wear it immediately, so we’re giving them that opportunity.” He acknowledges that “it’s very difficult for a company” to switch over the production, since it essentially requires you to redo “your entire manufacturing calendar,” but in the case of TommyxGigi—when they were speaking to a younger audience, a global audience, and an audience that wants to copy Hadid’s each and every outfit as soon as possible—it made sense. “It’s strange when something comes out and [fans] see all the celebrities wearing it but they can’t get it," added Hadid. "It seems old by the time they can.”

Though rooted in classic Americana and the brand’s signature bold color palette, each TommyxGigi collection has followed a specific theme, somewhat related to the place Hilfiger and Hadid were hosting their show: The first one was New York, where they presented a carnival-inspired event on a pier; the second was in L.A. and drew from the model’s California roots; the third was in London, and borrowed from the musical venue that served as the backdrop; the fourth and final took the #TommyxGigi crowd to Milan for a racing-inspired extravaganza.

Given the range in source material, the collaboration has given us some pretty unique pieces over two years—and Hilfiger believes the pieces borne out of this partnership will turn into “collector’s items,” though not just because of aesthetics. “[TommyxGigi] was unprecedented in the industry, [as were] ‘see now, buy now’ fashion shows,” he noted. “We broke all the rules. We did something that had never been done before. That will be in the memory bank—in the history books.”

And in their own personal memories, there are a few things Hilfiger and Hadid hold dear, like the fact that Mother Monster is a fan. Both cite Lady Gaga as their most exciting celebrity TommyxGigi sighting: Hilfiger says it was Lady Gaga’s head-to-toe look for the L.A. show (“It was a moment”); Hadid recalls an Instagram the performer posted in which she’s wearing the Leopard Rock Jacket (“I thought it was so epic”). As fas as what TommyxGigi season-four outfit Gaga will pluck from the lineup, our money's on #48.

Check out every single look from the fourth and final TommyxGigi show, ahead.

Tommy Hilfiger paid for the author’s travel and accommodations for the purpose of writing this story.